diff --git a/linkedin_messaging/linkedin.py b/linkedin_messaging/linkedin.py
index 4595344..c82aa40 100644
--- a/linkedin_messaging/linkedin.py
+++ b/linkedin_messaging/linkedin.py
@@ -133,7 +133,7 @@ class LinkedInMessaging:
     ]
 
     _realtime_session_id: uuid.UUID
-    _realtime_connection_id: uuid.UUID | None = None
+    _realtime_connection_id: Optional[uuid.UUID] = None
 
     def __init__(self):
         self.session = aiohttp.ClientSession()